LIBRARY OF CONGRESS. 



Blie]f-TTtl7 

UNITED STATES OF AMERICA. 



fliiitl@ii iii 4iiw©ii 



FOR 



STEPHEN ROPER, Engineer, 
Author of " Roper's Practical Hand-Books on Steam Engineering." 



PHILADELPHIA: 

E. CLAXTON & COMPANY, 

No. 930 Market Street. 



4®=" Copies Mailed on Receipt of Price, $3.00. 






Entered according to Act of Congress, in the year 1880, by 

STEPHEN ROPER, 
in the Office of the Librarian of Congress, at Washington. 






INTEODUCTION. 



THE following Questions embrace all that any 
engineer would be likely to be asked when un- 
dergoing an examination, but, of course, not one- 
quarter of them will ever be asked at any one ex- 
amination ; nevertheless, as the examiners have the 
right to vary the questions, it may be advisable for 
the candidate to make himself conversant with them 
all. Moreover, supervisors, when examining men 
for licenses as engineers in the mercantile marine, 
ask the same questions that the board of examiners 
fbr the United States revenue service do, and vice 
versa J while engineers applying for certificates to 
take charge of stationary steam-engines are, in 
many instances, asked similar questions. In regard 
to this latter class, the inquiry is generally directed 
to ascertain their knowledge of steam-boilers and 
skill in their care and management. 

iii 



IV INTRODUCTION. • 

But the questions and answers contained in this 
little book were not intended to meet all the re- 
quirements of a thorough preparation, but rather to 
suggest to candidates the nature of the questions 
that will be asked in a majority of cases, and the 
sources from which they might obtain ample infor- 
mation on each subject. No one is to blame for not 
being well informed on subjects on which he did 
not know where to obtain information ; but, when 
once informed where it can be procured, if he fails 
to avail himself of the opportunity of so doing, he 
deserves no sympathy in his embarrassing position. 
Full information on every subject alluded to in the 
Questions and Answers may be found in Roper's 
Hand-Books for engineers. 

There is too much laxity among engineers in 
general in regard to procuring valuable and import- 
ant information on subjects relating to their call- 
ing. Legislation, that would require every one 
about to engage in this important calling to dem- 
onstrate that he understood the rudiments of the 
business, would have a salutary effect, and give 
guarantees of safety in many instances where not 
one shadow of them exists at present. 

S. K 



KOPER'S 

Questions for Stationary Engineers."^ 



Q,. What would you do first on entering the boiler- 
room in the mornins: ? 

A. I would ascertain if the water was at the proper 
height. 

ft. Providing you thought the water was rather 
low, what course would you pursue ? 

A. I would start the injector or pump, providing I 
had sufficient steam to do so ; if not, I would allow 
the water to run in from the street main or from the 
tank, as the case might be. 

ft. How often ought a boiler to be cleaned ? 

A. As often as is practicable or convenient ; at 
least once in every six months: the oftener, the better. 

ft. How should boilers be treated preparatory to 
being cleaned ? 

A. They should be blown out and filled again, and 
the water allowed to remain in them until the clean- 
ing is about to be commenced. 

ft. What would be the object in allowing the water 
to remain in them up to the time of cleaning ? 

* See Roper's " Catechism of Steam-Engines." 
1* 6 



6 QUESTIONS FOR ENGINEERS. 

A. Tor the purpose of keeping the mud soft, and 
thereby preventing it from becoming firmly attached 
to the shell, tubes, etc. 

CI. What would you do before blowing out a boiler ? 

A. I would remove all the fire from the furnace. 

ft. What pressure should boilers be blown out under ? 

A. 35 to 40 pounds per square inch. 

ft. What would be the objection to blowing out the 
boiler under 100 pounds pressure per square inch ? 

A. The change of temperature would be so sudden 
that it would cause the boiler to contract rapidly, and 
induce leakage or fracture. 

ft. What effect has scale or deposit on steam- 
boilers ? 

A. It prevents the water from coming in contact 
with the plates, the result of which is the iron be- 
comes burned. 

ft. What is the effect of hard firing on steam- 
boilers ? 

A. In consequence of the heat being so intense the 
water is expelled from the plates, the result of which 
is that the fibre of the iron is destroyed and it be- 
comes granulated, and in many instances as brittle as 
glass. 

ft. Should dissolvents, which are placed in boilers to 
prevent and remove scale, be relied upon as effGctual 
remedies for the evils resulting from incrustation V 

A. No ; as they frequently loosen and throw down 
large masses of scale, which, unless removed by blow- 
ing out, washing, or scraping, will cause the boiler to 
be burned through at that point. ^ 

* See Roper's " Use and Abuse of the Steam-Boiler.'' 



QUESTIONS FOR ENGINEERS. - 7 

ft. What precaution would you take before starting 
a fresh fire,Wr opening the draught, after the boiler 
had been standing some time ? 

A. I would ascertain if the water in the boiler was 
at the proper level. 

ft. AVhen starting a fresh fire under a boiler filled 
with cold water, how would you allow it to burn ? 

A. If I had sufficient time to get up steam I would 
allow it to burn gradually, as to let it burn fast would 
be objectionable. 

ft. What would be the objection to allowing the fire 
to burn rapidly under a boiler filled with cold water ? 

A. Because it would produce unequal expansion 
and induce unnatural strains, in consequence of one 
side of the boiler becoming hot while the other was 
*cold. 

ft. What course would you purstie, if you discov- 
ered that the water was dangerously low in the boiler 
or boilers of which you have charge ? 

A.-I would not allow the water to become danger- 
ously low in any boiler that I had charge of; but, if it 
became low from circumstances over which I had no 
control, such as the pipe bursting or becoming stopped 
up, the well being pumped dry, or the supply being 
cut off, I would draw my fire. 

ft. Don't you think the most careful engineer or 
fireman would be liable to forget his water some- 
times?^ 

^ Do not ever admit that there would be any possibility of 
you forgetting anything connected with the care and manage- 
ment of steam-boilers, as such an admission would prevent you 
from getting a license. 



8 QUESTIONS FOR ENGINEERS. 

A. No. I cannot see any reason why he should 
forget. • 

ft. Don't you know that the oldest, most cautious 
and careful engineers are prone to forgetfulness ? * 

A.>That has not been my experience, consequently 
I am positive I would not forget the water supply, or 
anything else connected with the care and manage- 
ment of steam-boilers. 

ft. Providing the water supply was cut off tempo- 
rarily, what course would you pursue ? 

A. I would shut down the engine, cover my fire 
with fresh coal, shut the damper, open the furnace- 
doors, and retain the necessary quantit}' of water in 
the boiler until the supply would be restored. 

ft. Providing you had to shut down your en^jine for 
a short time, with a high pressure of steam on the 
boiler, what course would you pursue ? 

A. I would cover my tire with fresh coal, close the 
damper and open the furnace-door, and start the 
pump or injector, at short intervals, while waiting. 

ft. What would be the object in starting the pump 
or injector at short intervals ? 

A. To keep up the circulation of the water in the 
boiler, and prevent the plates directly in contact over 
and around the fire from becoming overheated and 
burned. 

ft. Would you disturb the safety-valve under such 
circumstance ? 

A. Ko ; as it might be attended with a certain 
amount of danger. 



See Roper's " P^ngineer's Handy-Book.' 



QX^ESTIONS FOR ENGINEERS. 9 

Q. What proportion should the area of the safety- 
valve bear to the grate-surface ? 

A. About one-half square inch of safety-valve area 
to one square foot of grate-surface.^ 

ft. Would a boiler carrying 100 pounds steam press- 
ure per square inch require a larger safety-valve than 
if the pressure was only 50 pounds per square inch ? 

A. No ; it might be smaller, as the higher the 
pressure the higher the velocity ; consequenth% a 
given volume of steam, at 100 pounds pressure per 
square inch, would escape through a smaller orifice 
and in less time than the same volume would if the 
pressure was only 50 pounds per square inch. 

ft. How often should the safety-valve be moved ? 

A. Every morning. 

ft. What would be the object in moving it every 
mornino- ? 

A. To see that it was in good working order. 

ft. How should safety-valves be treated ? 

A. They should be cleaned, repaired, and ground 
down to their seats as often as practicable. / 

ft. How could you tell whether the safety-valve 
was correctly marked or not ? 

A. I would observe the pressure on the steam-gauge 
when the steam was blowing off at the safety-valve, 
and if they nearly coincided I would consider them 
correct ; but, if there was much variation between 
them, it would be evident that one or the other of 
them was incorrectly marked or out of order. 

ft. How often should steam-gauges be tested ? 

*See Roper's ^* Use and Abuse of the Steam-Boiler.'* 



10 QUESTIONS FOR ENGINEERS. 

St. 

A. At least once a year, or whenever their record- 
ance was supposed to be erroneous. 

ft^What would you consider the duty of an engi- 
neer on taking charge of an engine or boilers for the 
tirst time in a strange place ? 

A. He should first see that the quantity of water in 
the boiler was ample, that the safety-valve was not 
overloaded, and that the steam-gauge was apparently 
in good order. He should next trace out all the pipes 
and connections between the water supply and the 
pump or injector, also between pump, the heater, and 
the boiler, and if the stop-cocks or valves were open 
or closed, according to their requirement of the ob- 
jects for which they were intended. 

ft. How often should boilers be tested and ex- 
amined?* 

A. As often as practicable ; once in every six 
months, at least. 

ft. Which, is the most practical way of testing 
steam-boilers ? 

A. Either by sounding them all over their surfaces 
inside and outside, their stays, braces, and all the ad- 
juncts and attachments, with a small steel hammer, 
for the purpose of determining if the boiler contains 
anycracks and flaws ; or by applying hydraulic tests. 

ft. How should the hydraulic test be applied ? 

A. The boiler should be blown out and filled again 
immediately, so that the heat remaining in the boiler 
may be transmitted to the water, for the purpose of 
warming it, as the temperature of the water in the 

*See Roper's '* Use and Abuse of the Steam-Boiler." 



QUESTIONS FOK ENGINEERS. 11 

boiler should never be less than 160^ Fahr. when the 
test is applied. 

ft. Would a boiler be stronger when subjected to 
any given steam pressure than if subjected to the 
same cold water pressure ? 

A. Yes, as the iron toughens with the heat up to 
500° Fahr. A boiler will be less liable to burst under 
80 pounds per square inch in pressure than the same 
boiler would be when subjected to 70 pounds per 
square inch cold water pressure. 

ft. Are steam-boilers frequently injured by the hy- 
draulic test ? 

A. Yes ; many boilers are strained and fractured 
by an injudicious application of it. 

ft. What is the meaning of the terms "longitudinal 
and curvilinear seams " ? 

A. The term ''longitudinal" means the seams run- 
ning along the side of the boiler, while the "curvi- 
linear" are those running around the circumference. 

ft. Why are the longitudinal seams generally double- 
riveted, while the curvilinear are only single-riveted ? 

A. Because there is twice the strain on the longi- 
tudinal that there is on the curvilinear seams. 

ft. What is the meaning of the term "tensile 
strength"? 

A. The term "tensile strength" means the resist- 
ance that boiler-plates would offer on being pulled 
apart on a straight pull in the direction of the grain 
or fibre of the iron. 

ft. Is it advisable to leave some cock or valve open 
on steam-boilers while they are being filled with cold 
water ? 



12 QUESTIONS FOR ENGINEERS. 

A. Yes, as it allows the air to escape, and facilitates 
the filling of the boiler. 

ft. Is it advisable to lift the safety-valve after a fresh 
fire has been started under it, when the boiler is filled 
with cold water ? 

A. Yes, as it allows the air which passed in with 
the water to escape, and which would otherwise pre- 
vent uniform expansion of the boiler. 

ft.^What are the objects of braces in steam-boilers? 

A, Tliey are a subterfuge for strength or to remedy 
weaknesses arising from wear or design. 

ft. Give the names of the different braces employed 
in strensftheninsf steam-boilers. 

A. The vertical and horizontal, angle, toggle, dome, 
and crown braces ; as well as the buckles, crow-feet, 
angle-irons, girths, stay-bolts, and leg braces. The 
tubes answer for braces for the tube-sheets ; the crow- 
feet for the crown and dome.^ 

ft. Give the rule for finding the safe working-pres- 
sure of any boiler. 

A. Multiply the thickness of iron by 56, if single- 
riveted, and 70, if double-riveted ; multiply this pro- 
duct by 10,000 (safe load) ; then divide this last pro- 
duct by the external radius (less thickness of iron) ; 
the product will be the safe working-pressure in 
pounds per square inch, which, if multiplied by 5, 
would give the bursting pressure.! 

ft. Why do you multiply the thickness of the iron 
by 56? 



■-•• See Roper's ** Engineer's Handy-Book." 

f See Roper's ^* Use and Abuse of the Steam-Boiler." 



QUESTIONS FOR ENGINEERS. 13 

A. Because the iron loses 44 per cent, of its strength 
in the process of punching. Double -riveted seams 
equal 70 of the original strength. 

ft. What do you mean by the external radius ? 

A. The radius of any cylindrical vessel is half its 
diameter, and by taking half the diameter of a steam- 
boiler, and subtracting the thickness of iron from it, 
we get the internal radius. 

ft. What do you mean by 10,000 safe load ? 

A, The tensile strength of boiler iron is generally 
capable of resisting a strain of 50,000 pounds per 
square inch, and one-fifth of that, or 10,000, is taken 
as safe load. 

ft. What is the meaning of tbe term "heating-sur- 
face"? 

A. It means all that portion of the steam-boiler ex- 
posed to the action of the fire and the heated gases in 
their escape from the furnace to the chimney. 

ft. How many square feet of heating -surface is 
allowed per horse-power ? 

A. About 16 square feet. 

ft. What is the average allowance of grate-surface 
to the horse-power ? 

A. About three-fourths of a square foot. 

ft. Give the rule for finding the weight necessary 
to put on a safety-valve lever, when the area of valve, 
pressure, etc., are known ? 

A. Multiply the area of valve by the pressure in 
pounds per square inch ; multiply this product by the 
distance of the valve from the fulcrum ; multiply the 
weight of the lever by one-half its length (or its centre 
of gravity) ; then multiply the weight of valve and stem 



14 QUESTIONS FOR ENGINEERS. 

by their distance from the fulcrum ; add these last 
two products together ; subtract their sum from the 
first product, and divide the remainder by the length 
of the lever ; the quotient will be the weight required.^ 
Y ft. Give the rule for finding the pressure per square 
inch on a safety-valve when the area of valve, weight 
of ball, etc., are known. 

A. Multiply the weight of ball by the length of 
lever, and multiply the weight of lever by one-half 
its length (or its centre of gravity) ; then multiply 
the weight of valve and stem by the distance from 
fulcrum. Add these three products together. This 
sum divided by the product of the area of the valve, 
and it^ distance from the fulcrum, will give the press- 
ure in pounds per square inch. 

ft. 14 the boiler was too small for the engine, and 
you f(3^;5nd it difficult to keep up the speed, would you 
place extfra weights on the safety-valve lever for the 
purpose of carrying extra pressure ? 

A. ^o ; because such an act on the part of an en- 
gineer would be a piece of culpable recklessness. 

ft. If the water supply should fail from any cause, 
and your employer was anxious to finish up some 
work he had in hand, would you continue running 
until the water became dangerously low ? 

A. No. I would not run any risk on any consid- 
eration whatever, under the influence of my employer 
or any one else. 

ft. What kind of steam-boilers are you acquainted 
with ? 

•'•■ See Roper's " Use and Abuse of the Steam-Boiler." 



QUESTIONS FOR ENGINEERS. 15 

A. Kearly all kinds in use. 

ft. To what strains are different parts of steam- 
boilers subjected ? 

A. The shells are subjected to a tearing strain and 
the flues or tubes ^ to a crushing strain. 

ft. Would a steam-boiler resist as much pressure if 
exerted on the outside of the shell as if the same 
pressure was exerted on the inside ? 

A. Ko ; as pressure exerted on' the inside of a boiler 
has a tendency to preserve its cylindrical form, while 
that exerted on the outside has a tendency to destroy 
it. 

ft. What is the meaning of the term collapse, when 
applied to the flues of steam-boilers? 

A. The term collapse means to crush in or flatten. 

ft. Will a flue of a certain diameter and thickness 
of iron, 20 feet long, stand as much pressure before col- 
lapsing as a flue of the same diameter and same thick- 
ness of iron 10 feet long would ? 

A. No ; a short flue would stand twice as much 
pressure before collapsing as a long one. 

ft. What is the principal cause of boiler explo- 
sions ? 

A. Weakness in the shell or other parts of the 
boiler. 

ft. To what causes may such weakness be attrib- 
uted? 

A. Poor material, inferior workmanship, bad design, 
neglect, overpressure, excess of firing, etc. 

ft. Is there any mystery about boiler explosions ? 

^ See Roper's " Use and Abuse of the Steam -Boiler.'* 



16 QUESTIONS FOR ENGINEERS. 

A. ^o ; when such an event does occur, it is evident 
that the boiler did not possess sufficient strength to 
resist the pressure, or that the pressure was too great 
for the boiler. 

ft. Give the type and dimensions of the boiler you 
had charge of last. 

A. It was a return tubular ; diameter 48 inches, 14 
feet long, wrought-iron heads, thickness of iron in shell 
/e, 46 3-inch tubes, 15 square feet of grate surface, 
safety-valve 3 inches in diameter, working pressure 65 
pounds per square inch.^ 

ft. What kind of an engine had you charge of last ? 

A. Horizontal slide-valve ; diameter of cylinder 12 
inches, stroke 24 inches, number of strokes 150 per 
minute, steam pressure 55 pounds per square inch, 
steam cut-off at half stroke by means of a positive cut- 
off (or lap on the valve). 

ft. What kind of a steam-gauge did you have? 

A. A spring gauge. 

ft. Did you use a pump or injector ? 

A. Both were used. 

ft. What sized pump or injector would you consider 
sufficient for any steam-boiler ? 

A. One that would throw a cubic foot of water 
every hour for every horse-power for which the boiler 
was rated. 



* Every engineer should know the exact size of the boiler in 
his charge ; the diameter, length, thickness of iron, number and 
diameter of tubes or flues, area of safety-valve, square feet of 
grate surface ; he should also know the proportion of the engine, 
land^yvhether slide- or poppet-valve, automatic, cut-off, or throt- 
tling. 



QUESTIONS rOK ENGINEERS. 17 

ft. What are the causes which are most likely to 
keep pumps from working ?* 

A. Insufficiency of water, the suction-pipe becoming 
choked with mud, leakage in the pipes, the valves 
being prevented from taking their seats by straw, 
shavings, or other substances being carried in with the 
water, or the pump-valves becoming hot, thereby caus- 
ing the valves to expand and stick. 



QUESTIONS FOE MAEINE ENGINEERS. 

ft. How long have you served as a fireman ? 

A. ... years. 

ft. How long have you served in the engine-room 
at sea, and in what capacity ? 

A. ... years. 

ft. With what description of engines have you 
served at sea,^ paddle or screw, jet-condensing, sur- 
face-condensing, or non-condensing engines, com- 
pound, trunk, inverted, or oscillating ; and what size 
were they ? 

A. The engines of the steamboat were x 

..^........., and the engines on the steamship on which 

I was engineer were ..,. x , surface con- 
densing, compound or simple, or jet-condens- 
ing, as the case may be. 

ft. Explain the difterence between condensing and 
non-condensing engines. 

A. In the case of the condensing engine, the steam 
is exhausted into a condenser ^ while in the case of 

* See Roper's " Hand-Book of Modern Steam Fire-Engines.'* 
2^ B 



18 QUESTIONS FOR ENGINEERS. 

the lion-condensing, it is exhausted into the atmos- 
phere. 

ft. What is the difference in effect between con- 
densing and non-condensing engines ? 

A. A condensing engine will develop as much 
power, with 35 pounds pressure per square inch, as a 
non-condensing of the same size would with 50 pounds 
13er square inch. 

ft. Explain the difference between jet- and surface- 
condensers. 

A. In the surface-condenser the steam is condensed 
by being brought in contact with a cold surface, while 
in the jet-condenser the steam is condensed by the 
introduction of cold water into the condenser. \ 

ft. Explain the advantages of jet- or surface-con- 
densers. 

A. As in the case of the surface-condenser, the in- 
jection water fs not mixed with the water of conden- 
sation ; the boilers are at all times supplied with 
fresh water ; thus preventing the formation of scale, 
making a saving in the consumption of fuel, and in- 
creasing the durability of the> boiler; while in th* 
case of the jet-condenser, the injection water mixes 
with the water of condensation, and, as a portion of 
it has to be taken to supply the boiler, which has the 
effect of forming scale, induces wastefulness of fuel, 
ending eventually in the destruction of the^boiler.* 

ft. Has the air-pump the same amount of duty to 
perform in the case of surface- and jet-condensers ? 

A. No. In the surface-condenser the air-pump has 

*-See Roper's ^^ Engineer's Handy-Book." 



QUESTIONS FOR ENGINEERS. 19 

only to extract the air and the water of condensation ; 
while in the case of the jet-condenser, it has to ex- 
tract the air, the water of condensation, and the in- 
jection water. 

ft, "What do you mean by the terms injection water 
and water of condensation ? 

A. The injection water is the water introduced inlll^ 
the condenser for the purpose of condensing the 
steam ; while the water of condensation is water 
which results from the condensation of the steam. 

ft. What is the meaning of the term " vacuiy» " ? 

A. A void, or empty space, where thete i^^ther 
water, steam, nor air. 

ft. How is a vacuum created in the condenser be- 
fore the engine is started ? 

A. By opening the snifting-valve and allowing the 
steam to go through and Ikpel the air ; then by 
closing the snifting-valve aniftntroducing the injec- 
tion water, when the vacuum is produced. 

ft. How is the vacuum maintained in the con- 
den^ ? 

A. By the injection water and the air-pump.* 

ft. Can a perfect vacuum be maintained ? 

A. Ko. 

ft. How much steam will a cubic inch of water pro- 
duce at the pressure of the atmosphere, or 15 pounds 
to the square inch ? 

A. 1728 inches, or one cubic foot. 

ft. How much injection water does it require to 
condense steam ? 

* See Roper's ** Engineer's Handy-Book." 



20 QUESTIONS FOR ENGINEERS. 

A. About twenty-one times the quantity from which 
the steam was generated.^ 

ft. What proportion does the cooling surface of th(5 
condenser bear to the horse-power of the engines 
with which they are connected ? 

A. About 6J square feet to the indicated horse- 
^|)Ower. 

ft. What proportion does the air of the circulating 
pump bear to the cooling surface in surface-con- 
densers ? 

A. About one cubic foot of capacity of circulating 
pun^ Mto oOl^feet of cooling surface in the condenser. 

ft. ^Pwhat material are the tubes of surface-con- 
densers usually made ? 

A. Either of brass or copper. 

ft. What proportion should jet-condensers bear to 
the capacity of the cy^der ? 

A. They should be^om j\ to 2V of the capacity 
of the steam-cylinder. 

ft. What is the most economical temperature at 
which to keep the water in the hot-well ? 

A. FromlOQotollOOFahr. ^ 

ft. What would be the effect of a higher or lower 
temperature ? 

A. A higher temperature would affect the vacuum, 
while a lower temperature would induce a loss of 
heat, and consequently would be a waste of fuel. 

ft. What causes would be most likely to impair the 
vacuum ? f 

A. An insufficient supply of injection water, leak- 

^' See Roper's " Engineer's Handy-Book." 
t See Koper's " Engineer's Handy-Book." 



QUESTIONS FOR ENGINEERS. 21 

age of the condenser in the air-pump or in any of 
the connections. 

• Q,. How is the exact amount of vacuum deter- 
mined ? 

A. By the vacuum-gauge. 

ft. What is the meaning of 16 inches of mercury, 
etc. ? 

A. As two inches of mercury represent one pound 
pressure ; 16 inches represent an 8-pound vacuum ; 
18 inches a 9-pound ; 20 inches a 10-pound, and so on. 

ft. Explain the difference between simple and com- 
pound engines, 

A. In simple engines the steam is used once ; after 
which it is exhausted into the atmosphere or con- 
denser ; while in the compound engines the volume 
of steam is used twice : as it is admitted from the 
small cylinder to a large one, and then escapes 
through the condenser. 

ft. What is the meaning of the term marine en- 
gine? 

A. It has no definite meaning.^ 

ft. What parts of marine engines are most likely to 
disable a ship in case of breakage ? 

A. If the piston-rod, crank-pin, crank, connecting- 
rod, cross-head, or valve-rod should break, it would 
disable the ship, if there were none on board to re- 
place them. 

ft. Providing a crank-pin, main-bearing, or truss- 
block should heat excessively, what course would you 
pursue ? 

A. I would oil them frequently ; and if that did not 

* See Roper's " Engineer's Handy-Book." 



22 QUESTIONS FOR ENGINEERS. 

prevent the heating, I would turn a stream of cold 
water on them from a hose. 

ft. Providing your pump failed to work, your water 
was low, and you were likely to be driven ashore, 
what course would you pursue ? 

A. I would head the vessel to the sea, and proceed 
in that direction until I could remedy the difficulty. 

ft. What causes would be most likely to prevent a 
pump from working ? 

A. See answer on page 17. 

ft. If the follower-plate should break at sea, what 
course would you pursue ? 

A. I would attempt to repair it with boiler-plate 
and tap-bolts, provided these materials were on 
board ; if not, I would detach the propeller-shaft and 
proceed under sail to the nearest port. 

ft. Providing the air-pump-rod should break, and 
there was no extra rod on board, how would you act ? 

A. I would remove the air-pump bucket and foot- 
valve, and rig a temporary exhaust-pipe with lumber, 
and work the engine non-condensing. 

ft. If the cylinder-head should be fractured or split, 
what course would you pursue ? 

A. I would attempt to repair it with pieces of iron, 
plank, and canvas, or whatever other material I could 
find on board. If I failed, I would draw my fires and 
proceed under sail. 

ft. If the cut-ofi* should break at one end? 

A. I would remove it from the other end and work 
steam whole-stroke. 

ft. If the crank-pin should break, what course 
should you pursue V 



QUESTIONS FOR ENGIXEERS. 23 

A. I would remove the broken pin by heating it 
with fire, and replace it with a new one, providing 
there was one on board. If not, I would detach the 
propeller-shaft and proceed under sail. 

ft. If the propeller-shaft should twist off, what 
course would you pursue '? 

A. I would disconnect it from the engines, and pro- 
ceed under sail. 

ft. Give the names of the different pipes, cocks, and 
valves used in connection with marine engines. 

A. See Koper's ''Engineer's Handy-Book," page 
•231. 

ft. WJi^at are the functions of the air-pump used in 
connection with the steam-engine ? 

A. To extract the air, the injection-water, and the 
water of condensation. 

ft. What relative proportion should the air-pump 
bear to the steam-cylinder ? 

A. The capacity of the air-pump should be about 
J15 of the capacity of the steam-cylinder. 

ft. What is the object of the marine steam-engine 
register or counter ? 

A. To tell the number of revolutions that the en- 
gine made on the passage. 

ft. Give the rule for finding the number of revolu- 
tions the engine has made during the voyage. 

A. Subtract the number at which the counter stood 
at the beginning of the voyage from that which is in- 
dicated at the end of it ;. the remainder will be the 
number of revolutions made during the voyage.^ 

* See Roper's " En^ueer's Handy-Book.'' 



24 QUESTIONS FOR ENGINEERS. 

Q. What is the object of the salinometer ? 

A. To tell the quantity of saline matter in the 
water in the boilers of marine engines. 

ft. What are the functions of the barometer ? 

A. The barometer is an instrument used for observ- 
ing the pressure and elasticity, or variations in dens- 
ity, of the atmosphere.* 

ft. Explain the difterent marine light, whistle, and 
bell signals for river and lake boats and ocean steam- 
ers. 

A. See Eoper's "Engineer's Handy-Book," pages 
389-391. 

ft. Explain the meaning of the term ''pitch of the 
screw," when employed in relation to screw-propel- 
lers used for the propulsion of vessels. 

A. The ''pitch of the screw " is the distance that 
it would advance in one revolution, if working in a 
solid, fixed nut ; or it is the distance between the 
threads measured in a line with the shaft. 

ft. Explain the meaning of the term "slip of the 
screw." 

A. The term "slip of the screw" means the differ- 
ence between the actual advance of the propeller 
through the water, and the advance which would be 
accomplished, if there was no recession of the water 
jiroduced by the pressure of the propelling surface.! 

ft. Upon what condition do the advantages of the 
paddle-wheel depend ? 

A. On the amount of its immersion in the water. 



- See Roper's " Engineer's Handy-Book." 

I See Roper's " Hand-Book of Land and Marine Engines.'^ 



7\ 

QUESTIONS FOR ENGINEERS. 25 

ft. What is the meaning of the term ''slip of the 
paddle"? 

A. The difference between the speed of the ship 
and that of the wheel. 

ft. Give the rule for finding the safe working-press- 
ure of a boiler, the diameter and the thickness of iron 
being known. 

A. See page 12. 

ft. Give the pames of the different adjuncts of 
steam-boilers. 

A. See Koper's "Engineer's Handy-Book," pages 
476-478. 

ft. How high will an ordinary pump lift water ? 

A. 33 feet. 

ft, What is the object of placing an air-vessel on a 
pump ? 

A. To induce a better supply of water, and prevent 
concussion or jar whenever the piston strikes the 
water. ^ 

ft. Give rule for finding diameter of pump-plunger 
for any engine. 

A. The diameter of the steam-cylinder multiplied by 
0*3 will give the proper diameter of pump-plunger. t 

ft. Give the names of the different minerals that 
constitute the basis of scale in steam-boilers. 

A. The minerals which constitute the basis of the 
scale which forms in steam-boilers using fresh water 
from wells, lakes, or rivers, are, sulphate of lime, 
phosphate of lime, carbonate of lime, magnesia, silica, 

* See Eoper's *' Hand-Book of Modern Steam Fire-Engines.'* 
f See Rope/s "Engineer's Handy-Book." 
3 



26 QUESTIONS FOR ENGIKEERS. 

and ajumina, with small quantities of sesquioxide of 
iron, baryta, carbonic acid, organic matter, chlorine, 
sulphuric acid, potassa, calcium, soda, phosphoric 
acid, magnesium, etc. The remedies for the preven- 
tion and removal of scale are almost innumerable. 

ft. Explain the cause of foaming in steam-boilers. 

A. Foaming in marine boilers using jet-condensers 
is generally caused by changing the water from salt to 
fresh, and vice versCc; the boiler being foul, insufficient 
steam-room, etc. 

ft. Give the meaning of the term "- priming." 

A. The term priming is understood by engineers to 
mean the passage of water from the boiler to the 
steam-cylinder in the shape of spray. 

ft. Give the meaning of the term "corrosion," and 
explain its analogy to combustion. 

A. The term corrosion means wasting, pitting, or 
grooving of the material, and is generally referred to 
under two heads, namely, internal and external. Ex- 
ternal corrosion is said to be due to the galvanic ac- 
tion of the mineral in the fuel and the gases in the 
atmosphere, and both are intimately associated with 
combustion, or stimulated by it. The acids and min- 
erals which are in solution in the water, and liber- 
ated by the heat, attack the boiler internally ; and the 
sulphur which is liberated by the combustion of coal 
has a strong affinity for the iron, and attacks it ex- 
ternally. 

ft. Give the rule for finding the horse-power of 
steam-engines. 

A. Multiply the area of the piston by the average 
pressure in pounds per square inch ; multiply this pro- 



QUESTIONS FOR ENGINEERS. 27 

duct by the number of feet the piston travel^ in a 
minute, and divide by 33,000. The quotient will be 
the horse-power. 

ft. Give the rule for finding the horse-power of 
steam-engines from indicator diagrams. 

A. Multiply the area of the piston by its travel in 
feet per minute, and divide by 33,000 ; the quotient 
multiplied by the mean effective pressure shown by 
the diagram will be the horse-power.* 

ft. Give the names of the different designs of steam- 
engines in use. 

A. Horizontal, vertical, inclined, oscillating, trunk^ 
geared, steeple, etc.* 

ft. Give the names of the different classes into 
which engines are subdivided. 

A. Single-acting, double-acting, direct-acting, back- 
action, etc.t 

ft. Give the different terms employed in expressing 
the horse-power of steam-engines. 

A. Kominal, indicated, actual, nett, dynamometri- 
cal, commercial horse-power, etc. 

ft. What is the nominal horse-power of a steam- 
engine ? 

A. 33,000 pounds raised one foot high in one min- 
ute ; 150 pounds raised 220 feet high in the same time^ 
or 550 pounds raised one foot high in one second. 

ft. Howmay these different units of weight be raised? 

A. By belts, pulleys, cog-gearing, cables, paddle- 
wheels, propellers, or such other mechanical applica- 
tions as are most practicable and convenient. 

* See Roper's " Engineer's Handy-Book." 

I See Roper's *' Hand-Book of Land and Marine Engines.'* 



28 QUESTIONS FOR ENGINEERS. 

NECESSARY QUALIFICATIONS 

FOR 

FIRST ASSISTANT E:^rGmEERS IK THE U. S. 
REYEISrUE-CUTTER SERVICE. 

First. They must pass before the board of exam- 
iners a thorough examination upon the subjects pre- 
scribed for second assistant engineers, and be able to 
explain the principles, peculiarities, functions, and 
uses of the different kinds of valves and valve-gear, 
as applied to marine steam machinery. 

Second. They must understand the construction, 
principles, peculiarities, and uses of the various me- 
chanical arrangements employed in working steam 
expansively. 

Third. They must understand the construction of the 
marine boilers in most general use, their attachments, 
and the functions and uses of the same. 

Fourth. They must be able to explain the most 
general causes of derangement in the operation of air- 
and feed-pumps and pipes, and the most practicable 
method of preventing and remed^dng them. 

Fifth. They must have a knowledge of the chemical 
and mechanical causes which induce the formation 
of scale in steam-boilers, and the most practicable 
method of preventing and removing the same. 

Sixth. They must be acquainted with the general 
construction, principles, peculiarities, and uses of the 
different kinds of surface-condensers in present use. 

Seventh. They must be able to calculate the loss 
induced by blowing ofi', for the purpose of keeping the 



QUESTIONS FOR ENGINEERS. 29 

water in the boilers at a uniform degree of saturation, 
and understand the principles of the various instru- 
ments employed to determine the water's saturation, 
as well as the method of graduating them. 

Eighth. They must understand the principles, most 
practicable limits, and ax3 vantages of working steam 
expansively, and be able to calculate the same. 

Ninth.* They must have a knowledge of the con- 
struction of the indicator, know how to apply it, and 
intelligently explain its diagrams. 

Tenth, They must be acquainted with the con- 
struction and the principles on which the action of 
steam- and vacuum-gauges is based, and the cai^ses 
of their derangement. 

Eleventh. They must have experience in building, 
erecting, and repairing steam machinery. 

Twelfth. Candidates for appointment as second as- 
sistant engineers must not be less than twenty-one 
nor more than thirty years of age ; they must be of 
good moral character find correct habits ; they must 
have worked not less than eighteen months in a 
steam-engine factory, or served the same period as an 
engineer on board of a steamer having a condensing 
engine ; they must also produce favorable testimo- 
nials from the superintendent of the machine-shop, or 
chief-engineer of the steamship, as to their ability. 

Thirteenth. They must be able to describe and sketch 
the different parts of marine steam-engines and boil- 
ers, and explain their uses and mechanical move- 
ments, the method of putting them in operation, 
regulating their action, and guarding against danger. 

Fourteenth. They must be fair arithmeticians and 
3* 



30 QUESTIONS FOR ENGINEERS. 

have a knowledge of rudimentary mechanics, be ca- 
pable of writing a fair, legible hand, and have some 
knowledge of chemistry, particularly of combustion 
and corrosion. 

Fifteenth. Candidates who excel in practical expe- 
rience and professional skill will be given the prefer- 
ence, both in admission and promotion. 

Sixteenth. Any candidate producing a false certifi- 
cate of age, time of service, or character, or making 
a false statement to the board of examiners, will be 
dropped from the list. 

ft. Give the rule for finding the quantity of coal 
rec[uired to drive a steamshij) a given number of days 
in average fair weather. 

A. The beam in feet squared will give the quantity 
of coal required in nett tons. 

ft. Give the rule for finding the percentage of loss 
induced by blowing off to prevent saturation. 

A. Multiply loss by blowing off by 100, and divide 
the product by the total degrees of heat imparted to 
the water, plus the heat lost by blowing off. (Observe 
that for ^2 ^s twice as much water is converted into 

steam as is blown off. For ^3, the amount is equal. 

"1 3 
For ^f , the amount is f , and so on. ) The result is the 

percentage of loss."^ 

ft. Give the rule for finding the amount of gain de- 
rived from working steam expansively. 

A. Divide the length of the stroke in feet by the 
cut-off, J, J, f , as the case may be ; then find, on the 
table on page 68 in Eoper's ''Engineer's Handy- 

*See Roper's " Engineer's Handy-Book." 



QUESTIONS FOR ENGINEERS. 31 

Book," the hyperbolic logarithm nearest to that of 
the quotient, to which add 1. This sum will give the 
ratio of gain. 

ft, Grive the rule for finding the mean or average 
pressure in the cylinder of a steam-engine. 

A. Divide the length of the stroke in inches (in- 
cluding the clearance) by the distance that the steam 
follows the piston before being cut off; the quotient 
will be the expansion the steam undergoes. Then 
find in the expansion column, in the following table, 
the number corresponding to it ; take the multiplier 
opposite, and multiply the full pressure of the steam 
per square inch, as it enters the cylinder, by it. The 
product will be the average pressure.* 

ft. Give the rule for finding the point of cut-off 
required to produce a given terminal from a given 
initial pressure. 

A. Divide the total terminal by the total initial 
pressure. The quotient will be the point of cut-off 
in decimal parts of the stroke. 

ft. Give the rule for finding the point of cut-ofF 
when the initial and mean pressures are known. 

A. Add the pressure of the atmosphere to the initial 
and mean pressures, and divide the mean pressure by 
the initial. Then find in the table of multipliers, 
page 69 of Eoper's "Engineer's Handy-Book," the 
number nearest to the quotient. Find the number 
opposite to it in the expansion column, and divide 
100 by it ; the quotient will be the point of cut-ofi* in 
decimal parts of the stroke. 

*" See Roper's " Engineer's Handy-Book/' page 68, 



32 QUESTIONS FOR ENGINEERS. 

ft. What is the object and use of indicator dia- 
grams ? ^' 

ft. What can be ascertained from them?^ 

ft. How do they show the power exerted by an 
ensfine?^ 

ft. How does the diagram show the steam-press- 
ure ? ^ 

ft. How does it show the back pressure ? * 

ft. How does it show the setting of the valves?* 

ft. How does it sliow a leaky piston ? * 

ft. Sketch diagram, and explain it.* 

ft. How does the expansion curve show that the 
steam is throttled ? * 

ft. Show the point of cut-ofF on the diagram. * 

ft. Show the eifect of leaky piston and leaky 
valves.* 

ft. Show the effect of small ports.* 

ft. Show the effect of lead upon steam and exhaust 
valves.* 

ft. Give the rule for calculating the mean and ter- 
minal pressure from indicator diagrams.* 

ft. Give the meaning of the terms "atmospheric 
line," "admission line," "steam line," "expansion 
line," "exhaust line," "compression line," "boiler- 
pressure line," "vacuum line," "clearance line," 
and "line of counter-pressure."* 

ft. What is the meaning of the term " theoretic 
curve" ?* 

ft. What is force, motion, velocity, and momentum, 
gravity, percussion, inertia ? * 

*See Roper's "Engineer's Handy-Book," Part IV. 



QUESTIONS FOR ENGINEERS. 33 

CI. What is combustion ? 

A. The development of heat by chemical combina- 
tions. 

ft. What are the products of combustion ? 

A. Steam, carbonic acid, carbonic oxide, smoke, etc. 

ft. How is steam formed in boilers ? 

A. By ebullition, which is caused by the application 
of heat to the outside of the vessel containing the 
fluid. 

ft. AVhat is smoke ? 

A. The exhalation from burning substances.* 

ft. What is coke ? 

A. The substance left in the retorts after the gas 
from the coal has been expelled. 

ft. What is coal ? 

A. A black, combustible fossil of vegetable origin. 

ft. What is carbonic acid ? 

A. An elastic fluid formed from that portion of 
constituent carbon which has not chemically com- 
bined in the proportion of 16 of oxygen to 6 of carbon 
by weight. 

ft. Show the loss by blowing off* at diff*erent degrees 
of saturation.* 

ft. State the means most frequently resorted to to 
prevent foaming.* 

ft. How is scale formed in steam-boilers ? t 

ft. Show the gain derived from using a heater, t 

ft. How is scale removed from steam-boilers ? t 

* See Roper's " Engineer's Handy-Book." 

t See Roper's "Use and Abuse of the Steam- Boiler." 

J See Roper's " Hand-Book of Land and Marine Engines." 

C . 



34 QUESTIONS FOR ENGINEERS. 

ft. Explain the objects, functions, and mechanism 
of steam- and vacuum-gauges.^ 

ft. What are the advantages of spring over mercury 
steam-gauges, and vice versa ? t 

ft. Is there any gain in generating steam of high- 
pressure over that of low-pressure ? 

A. Yes ; because it is more expansive. 

ft. Explain the different appliances for working 
steam expansively. . 

A. See Roper's "Engineer's Handy-Book" on the 
subject of cut-offs. 

ft. What is the meaning of the term ''lead on the 
valve"? 

A. The amount of opening the valve has for the 
admission of steam when the pistou is at the com- 
mencement of the stroke. 

ft. What is the meaning of the term "lap on the 
valve"? 

A. The amount the valve overlaps each steam-port 
when in the centre of its travel. 

ft. What is foam? 

A. A mixture of steam and water. 

ft. Give the names of the different valves and 
valve-gear employed on all classes of steam-engines, t 

ft. Explain the difference in the mechanism of the 
Stevens, Winter, and Sickel cut-offs. 

A. See Roper's "Engineer's Handy-Book" on the 
subject of cut-oflfs. 

* See Roper's " Engineer's Handy-Book." 

t See Roper's " Hand-Book of Land and Marine Engines." 

J See Roper's ** Use and Abuse of the Steam-Boiler." 



QUESTIONS FOR ENGINEERS. 35 

ft. What would be the difference in effect between 
a condensing and non-condensing engine of the same 
size and working with equal boiler pressure ? 

A. A condensing engine would do as much work as 
the non-condensing with 14 pounds per square inch 
less pressure. 

ft. Give the approximate weights of different met- 
als.^ 

ft. To what order of levers does the safety-valve 
lever belong ? 

A. To the third order. 

ft. What elements are embraced in the mechanical 
powers ? 

A. The wheel and axle, inclined plane, wedge, pul- 
ley, and screw. "^ 

ft. What is geometry?^ 

ft. What is an axiom ?* 

ft. What is a theorem?"^ 

ft. What is a solution ? * 

ft. What is a corollary ?^ 

ft. AYhat is trigonometry ? ^ 

ft. What is corrosion ? 

A. Wasting away of material of which boilers are 
made, caused by chemical action of the acid in the 
water. 

ft. What is the meaning of the term ''travel of 
the valve"? 

A. The distance the valve moves on its seat. 

ft. What is the meaning of the term " throw of the 
eccentric " ? 

* See Roper's ** Engineer's Handy-Book." 



36 QUESTIONS FOU ENGINEERS. 

A. See Eoper's "Engineer's Handy-Book," subject 
"Eccentric." 

ft. What is the meaning of the term " cam ?' ? 

A. It has no definite meaning. 

ft. Does adding lap to the valve necessitate the 
altering of the position of the eccentric ? 

A. Yes.* 

ft. What would be the probable effect of an accu- 
mulation of water in the cylinder ? 

A. It would be liable to cause a fracture of the 
cylinder-head, the piston, or spring the joints. 

ft. How does the steam enter the cylinder ? 

A. Through the steam-ports. 

ft. How does the steam escape from the cylinder? 

A. In ordinary slide-valve steam-engines it escapes 
through the same openings by which it enters ; but in 
other arrangements it escapes by an independent ex- 
haust-valve. 

ft. What are the advantages of the ordinary slide- 
valve ? 

A. Simplicity of design, moderate first cost, and 
positive action. 

ft. What are its disadvantages ? 

A. Its wastefulness."^ 

ft. What are the advantages of poppet- or double- 
beat valves ? 

A. They are nearly balanced, and require very little 
power to work them. 

ft. What are the disadvantages of poppet- or double- 
beat valves ? 

* See Roper's "Catechism of High -Pressure or Non- Condens- 
ing Steam-Engines." 



QUESTIONS FOR ENGINEERS. 37 

A. They are difficult to keep steam-tight, and at 
high-piston velocities they would not seat. 

ft. What are the advantages of vertical over hori- 
zontal steam-boilers for marine purposes ? 

A. Economy of space. 

ft. How much water can be evaporated by one 
pound of coal, in tubular boilers, under the best con- 
ditions ? 

A. About eight pounds. 

ft. What is the meaning of the term ''calor- 
imeter" ? 

A. Calorimeter means the area of the flue through 
which the hot gases escape from the furnace. 

ft. What is the meaning of the term " vent" ? 

A. The calorimeter of the flue in inches divided by 
its length in feet is termed the vent. 

ft. Give the height, weight, and component parts 
of air.^ 

ft. Into what two classes may pumps be divided ? 

A. Lift or suction and force ; and these, again, into 
single-acting, double-acting, rotary, centrifugal, buck- 
et-plunger, and solid piston. 

ft. Which of the foregoing pumps do you consider 
the best ? 

A. Each of them was designed for some special ob- 
ject, and probably meets the requirements of that 
better than any other. 

ft. What are the meanings of the terms " accelera- 
tion," ''affinity," '^ angle," "axle," "capillary 
attraction, " " friction, " " gravity, " " g^^ration, ' ' 

* See Roper's *' Engineer's Handy-Book." 



38 QUESTIONS FOR ENGINEERS. 

"hydrodynamics," ''hyperbola," "impact," "im- 
penetrability," "impetus," "incidence," "incli- 
nation," "inclined plane," "inertia," "mass," 
"matter," "mechanical powers," "modulus," "mo- 
mentum, " " motion, " " oscillation, " " percussion, ' ' 
"pneumatics," "power," " prime movers, " "statics," 
"tools," "tortion," "velocity," "weight," and 
"work"? 

A. See Eoper's "Engineer's Handy-Book," under 
the head of "Central and mechanical forces." 

ft. Specify the different kinds of motions recognized 
in mechanics. 

A. Absolute, accelerated, angular, compound, nat- 
ural, parallel, relative, retarded, uniform, and rotary.^ 

ft. What is the cause of draught in chimneys ? 

A. Draught is caused by the difference in weight of 
a column of rarefied air passing over or through a fire 
and that of the atmosphere at an ordinary tempera- 
ture. 

ft. How much steam-room would you allow in a 
steam-boiler ? 

A. About one-fourth of the cubic contents. 

ft. "What are the meanings of the terms "water- 
space" and "steam-room" when applied to steam- 
boilers ? 

A. The term water-space means that part occupied 
by the water, while the term steam-room is the part 
occupied by the steam. 

ft. What is the object in using a gib and key on the 
stub-ends of a connecting-rod ? 

*' See Roper's " Engineer's Handy-Book." 



QUESTIONS FOR ENGINEERS. 39 

A. To take up the lost motion. 

ft. Why are stub-end straps made thicker at the 
point where^ the key passes through than at any 
other ? 

A. To compensate for the amount of material 
taken out in the slot. 

ft. What kind of condensers are you acquainted 
with ? 

A. With all kinds. 

ft What are the advantages of a surface-condenser 
over a jet-condenser '? 

A. They furnish fresh water to the boiler, thereby 
preventing scale, saving fuel, and also saving the 
boiler. 

ft. How does the injection-water enter the con- 
denser ? 

A. In the case of the jet-condenser, it rises through 
the ship's side and into the condenser, the quantity 
being regulated by a cock or valve ; while in the sur- 
face-condenser it is lifted from the sea, lake, or river, 
by the circulating-pump, and forced through the 
tubes. 

ft. How are the tubes of surface-condensers made 
tight ? * 

ft. What circumstances would be most likely to 
effect a vacuum ? 

A. Insufficiency of injection -water, leakage in the 
tubes, air-pump, or some of the connections. 

ft. What is the most advantageous point to cut off 
steam when used expansively ? 

-'■ See Roper's *' Engineer's Handy-Book.'' 



40 QUESTIONS FOR ENGINEERS. 

A. About five-eighths of the stroke. 

ft. How is scale prevented from forming in a boiler ? 

A. By using a surface-condenser and surface blow- 
off. 

ft. At what distance should the air-pump be placed 
from the condenser ? 

A. The air-pump should be as near the condenser 
as possible. 

ft. Should the air-pump be placed above or below 
the condenser ? 

A. It would be more advantageous to place it so 
that the openings of the air-pump would come on a 
line with the openings of the condenser.^ 

ft. Would a pump labor under any disadvantage 
when working salt water at one end and fresh water 
at the other end ? 

A. Yes ; there would be more strain at the end at 
which it was working salt water, on account of its 
being more dense. 

ft. Give the names of the different steam-boilers in 
most general use, their peculiarities of design, advan- 
tages, disadvantages, how fired, etc. 

A. Plain cylinder, horizontal, vertical, tubular, re- 
turn flue, drop flue, locomotive, double deck, fire and 
water, tubular, fire-box, etc. 

ft. How are steam-boilers in general fired ? 

A. The plain cylinder, return flue, and most of the 
tubular are fired externally, while locomotive and 
marine fire-box boilers are fired internally. Some 
designs of tubular boilers are fired internally. For 

*" See Roper's " Engineer's Handy-Book." 



QUESTIONS FOR ENGINEERS. 41 

full information on this subject, see Eoper's "Use 
and Abuse of the Steam-Boiler. " 

ft. How high must a conical- or poppet-valve lift to 
give an opening equal to its area ? 

A. One-half of its radius or one-fourth its diameter.^ 

Q,. Is the Sickel cut-off positive or adjustable ? 

A. Adjustable. 

ft. Is the Winter cut-off adjustable ? 

A. Yes. 

ft. Is the Stevens cut-off adjustable ? 

A. Yes. 

ft. From what part of the engine do the Stevens, 
Sickel, and Winter cut-offs receive their motion ? 

A. From the eccentric. 

ft. What objection is there to a Sickel valve-gear 
when a ship is laboring ? 

A. It will not release the valves ; and, as a resuU, 
the engine will jump and race. 

ft. Do you know any independent means of work- 
ing the valves of steam-ens^ines ? 

A. Yes, by hand. 

ft. Does the Stevens, Winter, and Sickel arrange- 
ment cut off at exactly the same point at each end of 
the stroke ? 

A. No. It would be impossible to equalize the 
cut-off when it receives its motion from an eccentric, 
on account of the angularity of the rod.f 

ft. Is it customary to give more lead on the lower 
steam-ports than on the upper ones, and if so, why ? 

* See Roper's " Hand-Book of Land and Marine Engines.'* 
t See Roper's '' Engineer's Handy-Book." 

4* 



42 QUESTIONS FOR ENGINEERS. 

A. Yes ; so as to compensate for the weight; of the 
piston, cross-head, connecting-rod, and crank. 

ft. How would you stop a steam-engine, provided 
the stop-valve was broken ? 

A. I would release or throw out the valve-srear, and 
move the valve entirely over both ports, by means of 
the*starting-bar. 

ft. Provided your eccentric slipped on the shaft, 
how would you proceed to adjust it ? 

A. I would place the crank on the dead-centre, re- 
move the bonnet of the steam-chest, and turn the 
eccentric around in the direction it is intended to 
run, until the valve had the proper amount of lead on 
that end. I would then make the eccentric fast, and 
place the crank on the other (centre ; and if the lead 
was the same at both ends, I would adjust the eccen- 
tric permanently ; if not, I would equalize the lead 
before so doing. 

ft. Is pressure weight ? 

A. Ko. Pressure exerts its force in every direc- 
tion, while weight presses only in one.* 

ft. How do you determine the pressure of steam in 
a steam-boiler ? 

A. There are three ways of ascertaining the press- 
ure in a boiler, — first by the gauge, second by the 
safety-valve, and third by the temperature. 

ft. How would you proceed to ascertain the press- 
ure, providing you had neither steam-gauge nor safety- 
valve ? 

A. I would take a bottle, or other vessel with a neck 



See Roper's " Engineer's Handy-Book.' 



QUESTIONS FOR ENGINEEKS. 43 

of sufficient width to admit a thermometer. I would 
then hold it under one of the gauge-cocks, or some 
other small pipe attached to the boiler, and allow the 
steafUi to flow in ; then, by withdrawing the thermome- 
ter quickly, the temperature would show the pressure^ 
as temperature and pressure are constant factors. 

ft. Can you illustrate the above explanation by an 
example ? 

A. Yes. Suppose the pressure was 15 pounds per 
square inch, the thermometer would register 212^ Fah. . 
if the pressure was 20 pounds, it would show 228.5°; 
if 40 pounds, 269. F; if 60 pounds, 295.6°, and so on. 

Any other questions, not contained in this book^ 
will be answered by the author on the application by 
letter, or otherwise, of any one who has purchased a 
copy. 

For all questions relating to cadetships in the 
United States Navy, see Roper's ''Engineer's Handy- 
Book.'' 







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45 



ROPER'S HAND-BOOKS FOR ENGINEERS. 



Hand-Book of the Locomotive, 

Including the Modelling, Construction, Running, and Man- 
agement of Locomotive Engines and Boilers. Fully Illus- 
trated. By Stephen Boper, Engineer. Tenth Edition, Be- 
vised, Enlarged, and Corrected. 18mo, tuck, gilt edge, $2.50. 

Catecliism of Hig^li-Pressiire or Non- 
Condensing' Steam-Engines, 

Including the Modelling, Construction, Bunning, and Man- 
agement of Steam-Engines and Boilers. With Illustrations. 
By Stephen Boper, Engineer. Twentieth Edition, Bevised 
and Enlarged. 18mo, tuck, gilt edge, $2.00. 

Hand-Book of Land and Marine Engines, 

Including tlie Modelling, Construction, Bunning, and Man- 
agement of Land and Marine Engines and Boilers, with the 
latest improvements in the same. Fully Illustrated. By 
Stephen Boper, Engineer. 600 pages. Tenth Edition, Be- 
vised and Enlarged. 16mo, tuck, gilt edge, $3.50. 

Iland-Book of Modern Steam Fire-Engines, 

Including the Bunning, Care, and Management of Steam 
Fire-Engines and Fire-Bumps. With Illustrations. By Stephen 
Boper, Engineer. Fourth Edition. It is the only book of the 
kind ever published in this country, as it contains an elaborate 
description of all Modern Steam Fire-Engines, Boilers, and 
Fire-Bumps, and is free from formulae or ultra mathematical 
expressions. 16mo, tuck, gilt edge, $3.50. 

The Engineer's Handy-Book, 

Containing a full explanation of the Steam-Engine Indicator, 
and its use and advantages to Engineers and Steam Users ; with 

46 



formulae for estimating the power of all classes of Steam- 
Engines ; also, Facts, Figures, Questions, and Tables for Engi- 
neers who wish to qualify themselves for the United States 
Navy, the Revenue Service, the Mercantile Marine, or to take 
charge of the better class of Stationary Steam-Engines. With 
Illustrations. By Stephen Roper, Engineer. $3.50. 

Use and Abuse of the Steam-Boiler, 

Including its Care and Management. With Illustrations. 
This is the only book ever published in this country devoted 
exclusively to Steam-Boilers. Sixth Edition. It contains illus- 
trations of all the different kinds of Steam-Boilers now in use, 
whether Stationary, Locomotive, Fire, or Marine ; and also of 
Sectional or Patent Boilers. By Stephen Roper, Engineer. 
18mo, tuck, gilt edge, $2.00. 

Questions and Answers for Eng^ineers. 

This little book contains all the Questions that Engineers 
will be asked when undergoing an examination for the purpose 
of procuring licenses. By Stephen Roper, Engineer. $3.00. 

Any of the foregoing books will be sent by mail, free of post- 
age, on receipt of publication price by 

STEPHEN KOPEK, 

447 North Broad St., Philad'a. 

Information by letter will be cheerfully given to parties mak- 
ing inquiries about Scientific Books, Steam-Engines, Boilers, 
Steam-Pumps, Injectors, or any kind of Steam Machinery. 
The Horse-Power of Steam-Engines, Heating. Surface of Steam- 
Boilers, and Speeds of Machinery accurately calculated, on ap- 
plication by letter or otherwise. Instructions given in all 
branches of steam-engineering. 

47 



